The effectiveness of WHO's interpregnancy interval advice
Authors: Md Nuruzzaman Khan, Shimlin Jahan Khanam
Journal: The Lancet Global Health (2023)

A short inter-pregnancy interval is a significant concern as it is associated with increased risks of adverse maternal and child health outcomes including maternal and child mortality, particularly in low-income and middle-income countries (LMICs). In 2005, WHO recommended intervals of 24 months before attempting the next pregnancy and 33 months before the next birth to promote healthier maternal and child health outcomes.1WHOReport of a WHO technical consultation on birth spacing: Geneva, Switzerland 13–15 June 2005. World Health Organization, Geneva2007Google Scholar This recommendation is not widely followed, particularly in LMICs.2Islam MZ Billah A Islam MM Rahman M Khan N Negative effects of short birth interval on child mortality in low- and middle-income countries: a systematic review and meta-analysis.J Glob Health. 2022; 1204070Crossref Scopus (2) Google Scholar The findings on outcomes of different inter-pregnancy intervals from available studies in LMICs are highly conflicting due to variations in defining the inter-pregnancy interval. Different studies have used various cutoff points and intervals, such as pregnancy-to-pregnancy interval, pregnancy-to-birth interval, birth-to-birth interval, and birth-to-pregnancy interval.2Islam MZ Billah A Islam MM Rahman M Khan N Negative effects of short birth interval on child mortality in low- and middle-income countries: a systematic review and meta-analysis.J Glob Health. 2022; 1204070Crossref Scopus (2) Google Scholar The second WHO recommendation advises women who have experienced pregnancy loss, whether due to miscarriage or induced abortion, to wait at least 6 months before attempting their next pregnancy.1WHOReport of a WHO technical consultation on birth spacing: Geneva, Switzerland 13–15 June 2005. World Health Organization, Geneva2007Google Scholar However, this guidance is also largely underused in LMICs. Adding to the complexity, evidence suggests that the time elapsed since the most recent pregnancy loss could have less effect on the outcome of the subsequent pregnancy for women who experienced early pregnancy loss.3Klebanoff MA Interpregnancy interval after stillbirth: modifiable, but does it matter?.Lancet. 2019; 393: 1482-1483Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar, 4Swaminathan A Fell DB Regan A Walker M Corsi DJ Association between interpregnancy interval and subsequent stillbirth in 58 low-income and middle-income countries: a retrospective analysis using Demographic and Health Surveys.Lancet Glob Health. 2020; 8: e113-e122Summary Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 5Wong LF Schliep KC Silver RM et al.The effect of a very short interpregnancy interval and pregnancy outcomes following a previous pregnancy loss.Am J Obstet Gynecol. 2015; 212: 375.e1-375.e11Summary Full Text Full Text PDF PubMed Scopus (25) Google Scholar This finding raises important questions that require further investigation. In The Lancet Global Health, Mohamed M Ali and colleagues6Ali MM Bellizzi S Shah IH The risk of perinatal mortality following short inter-pregnancy intervals—insights from 692 402 pregnancies in 113 demographic and health surveys from 46 countries: a population-based analysis.Lancet Glob Health. 2023; 11: 1544-1552Summary Full Text Full Text PDF Scopus (1) Google Scholar examine the effectiveness of both WHO recommendations and identify ineffective effects for the second recommendations. However, this sudy found no significant improvement in perinatal outcomes associated with delaying the next pregnancy after a loss. These cited studies also reported delaying pregnancy after a loss do not bring any improvement in perinatal outcomes.3Klebanoff MA Interpregnancy interval after stillbirth: modifiable, but does it matter?.Lancet. 2019; 393: 1482-1483Summary Full Text Full Text PDF PubMed Scopus (4) Google Scholar, 4Swaminathan A Fell DB Regan A Walker M Corsi DJ Association between interpregnancy interval and subsequent stillbirth in 58 low-income and middle-income countries: a retrospective analysis using Demographic and Health Surveys.Lancet Glob Health. 2020; 8: e113-e122Summary Full Text Full Text PDF PubMed Scopus (23) Google Scholar, 5Wong LF Schliep KC Silver RM et al.The effect of a very short interpregnancy interval and pregnancy outcomes following a previous pregnancy loss.Am J Obstet Gynecol. 2015; 212: 375.e1-375.e11Summary Full Text Full Text PDF PubMed Scopus (25) Google Scholar However, careful consideration and further research are needed before implementing this reported finding into practice due to uncertainties that the findings reported. Further comprehensive analysis is needed to inform decisions on pregnancy planning after a loss. The primary uncertainty in this study arises from the cross-sectional survey data, which come with their own limitations: the study design raises the possibility of recall bias, and findings are correlations rather than deductions of causation. Additionally, the authors extracted birth interval data from pregnancy calendars, which record completed reproductive history of women for 5 years to 7 years years before the survey data. This approach has recognised limitations, such as under-reporting of abortions.7Pullum TW Becker S Evidence of omission and displacement in DHS birth histories. ICF International, Maryland, USA2014Google Scholar Furthermore, comparing pregnancy outcomes in women that occurred between 5 years and 7 years earlier than the survey time under their current sociodemographic conditions might not accurately represent their social, demographic, and environmental context at the time of their pregnancy.8Khan MN Islam MM Women's experience of unintended pregnancy and changes in contraceptive methods: evidence from a nationally representative survey.Reprod Health. 2022; 19: 187Crossref PubMed Scopus (4) Google Scholar For instance, women who experienced a pregnancy loss could have resided in rural areas at that time but now live in urban areas, or they could have completed secondary education at the time of the pregnancy loss but now have completed higher education. Moreover, the authors of the referred study did not consider the nutritional status of the women at the time of the earlier pregnancy loss due to unavailability of relevant data, including undernutrition and anaemia, which are major risk factors for stillbirths and miscarriages.9Rahman MA Khan MN Rahman MM Maternal anaemia and risk of adverse obstetric and neonatal outcomes in South Asian countries: a systematic review and meta-analysis.Public Health Pract. 2020; 1100021Google Scholar Pregnancy losses from women with these conditions and women in good health cannot be treated as equivalent when examining their effects on subsequent pregnancies. Women with poor nutritional status could be at a higher risk of losing their second pregnancy if their nutritional condition remains unchanged.9Rahman MA Khan MN Rahman MM Maternal anaemia and risk of adverse obstetric and neonatal outcomes in South Asian countries: a systematic review and meta-analysis.Public Health Pract. 2020; 1100021Google Scholar Authors also excluded women with extreme preterm births (pregnancies with livebirths at 6 months of gestation) from the analysis. Although this is logical under the umbrella of the referred study, this group deserves a separate subgroup analysis to explore how previous pregnancy losses affect subsequent pregnancy outcomes. Although Ali and colleagues6Ali MM Bellizzi S Shah IH The risk of perinatal mortality following short inter-pregnancy intervals—insights from 692 402 pregnancies in 113 demographic and health surveys from 46 countries: a population-based analysis.Lancet Glob Health. 2023; 11: 1544-1552Summary Full Text Full Text PDF Scopus (1) Google Scholar performed a rigorous data analysis, several unmanageable challenges raise questions about the generalisability of the findings. The data analysed spanned two decades, from 2000 (covering the period 1996–2000) to 2021–22. During this time, the included countries underwent substantial changes, primarily due to rapid advancements in public health, increased focus on maternal and child health as part of the Millennium Development Goals (2000–15), and the ongoing implementation of Sustainable Development Goals (2015–30).10Syed U Kinney MV Pestvenidze E et al.Advancing maternal and perinatal health in low- and middle-income countries: a multi-country review of policies and programmes.Front Glob Womens Health. 2022; 3909991Crossref PubMed Scopus (2) Google Scholar The adverse outcomes reported in this study might thus not be very comparable with previous findings, as the underlying context has changed. It is also crucial to consider country-level differences in adverse outcomes that are heavily influenced by national policies and programmes.2Islam MZ Billah A Islam MM Rahman M Khan N Negative effects of short birth interval on child mortality in low- and middle-income countries: a systematic review and meta-analysis.J Glob Health. 2022; 1204070Crossref Scopus (2) Google Scholar Given these persistent challenges, it might be premature to regard existing WHO recommendations as ineffective in all contexts. However, this study could serve as a starting point for researchers to address these issues more comprehensively, possibly through cohort studies, in the years to come. We must remain mindful that we should not take any risks when it involves matters of human life. We declare no competing interests. The risk of perinatal mortality following short inter-pregnancy intervals—insights from 692 402 pregnancies in 113 Demographic and Health Surveys from 46 countries: a population-based analysisOur study reaffirms the WHO recommendation on optimal interval between the last livebirth and the next pregnancy of at least 24 months and avoiding pregnancy before 18 months. However, our analysis does not support the WHO recommendation of delaying the next pregnancy for at least 6 months after a pregnancy loss for improved perinatal survival. Full-Text PDF Open Access